1. Field of the Invention
The present invention relates to a low temperature storage cabinet such as a refrigerator, a freezer or the like, the cooling apparatus of which is controlled to maintain an internal temperature of the storage cabinet in a predetermined range between upper and lower temperature limits. The invention also relates to a display apparatus for indicating various abnormalities of the storage cabinet to the user or the serviceman. These abnormalities may include excessive flow of electric current to a compressor of the storage cabinet, excessive rise of temperature of the compressor, excessive rise or drop of the internal temperature of the storage cabinet, and disconnection or short of a temperature sensor in the storage cabinet.
2. Discussion of the Prior Art
In Japanese Patent Laid-open Publication No. 63-226578, there is disclosed a low temperature storage cabinet provided with a lamp to be turned on upon the occurrence of an abnormality in the storage cabinet. Japanese Utility Model Laid-open Publications Nos. 60-10383 and 60-10387 disclose a low temperature storage cabinet provided with a number of alarm lamps which are aligned to be turned on upon the occurrence of various abnormalities for indicating plural abnormalities in a binary notation.
In the former storage cabinet, however, it is impossible to recognize the nature of the abnormality. In the latter storage cabinet, the on-off operation of the alarm lamps make it difficult to identify the nature of the abnormalities by the user or the serviceman.
In these types of low temperature storage cabinets, various abnormalities will occur in a chain reaction due to one or more faults in the storage cabinets. The recognition of the respective natures of abnormalities is useful to find the fault or faults in the storage cabinet. In the prior art, however, it is very difficult to indicate to the user or the serviceman the respective natures of various abnormalities.